Method for the preparation of aluminum alloys for the extraction of the aluminum by means of mercury



April 27, 1954 G. MESSNER 2,676, METHOD FOR THE PREPARATION OF ALUMINUM ALLOYS FOR THE EXTRACTION OF HE ALUMINUM BY MEANS OF MERCURY Filed Oct. 19, 1950 M WW Patented Apr. 27, 1954 MINUBI ALLOYS FOR THE EXTRACTION OF THE ALUMINUM BY MEANS OF MERCURY Georg Messner, Johannesburg, Transvaal, Union of South Africa, assignor to Inventa 'A.-G. fuer Forschung und Patentverwertung Luzern, Lu-

cerne, Switzerland Application October 19, 1950, Serial No.191,092

l his. i ntion r la s t an m rove 'me for the preparation of aluminum have for the extraction of the aluminumby means ofmercury. It is a known fact that aluminum may be extracted fromalumin'um alloys by'treating said alloys with hot mercury, thereby dissolving the aluminuminthe hot mercury. w

It is a matter "of course that in carrying out this process it'will 'be necessary to: reduce the size of the starting material to small pieces in order to improve the contact possibilities between the aluminum alloy and the'mercury solvent.

4' Claims. (Cl. 18-1472) Despite extensive'dres'sing, however, the ex I traction of aluminum according to'th'e known methods proceeds veryslowly and may'no't start at all unless the temperature is brought to a certainheig'ht' j j It is noticeable that at'moderate temperature,

say 300 C.; at which the solubility'of aluminum in mercury is appreciable, themercury mostly shows no dissolving power, even if the material to be extracted hasbeenreduced to small size. In these cases, recourse may be taken to strongly increasing the temperature of the solvent at the beginning until solution begins to take place, whereupon the continuation of the extraction can take place at moderate temperature.

Hereby the mercury must, of necessity, pass through a range ofhigh vapor. pressure which makes the construction of the extraction apparatus more dimcult.

It is the object of this invention to overcome the disadvantages pointed out heretofore.

The inventor has found that the extraction of aluminum from aluminum alloy by means of mercury can be performed at relatively low temperatures if the preparation and dressing of the starting material is performed not in the presence of air but in the presence of mercury.

Therefore this invention relates to a process in which the starting alloy is surrounded by liquid or gaseous mercury when the physical feature of said alloy is changed in preparation for the extraction process.

In carrying out my invention, a number of difierent methods may be employed. Some examples will be given, in which several embodiments of the invention will be described and illustrated by the accompanying drawings:

It should, however, be understood that the examples are given by way of illustration and not of limitation and that many modifications in the details may be made without departing from the spirit of the invention.

In the drawings:

Fig. 1 shows partly in longitudinal section a device for carrying out the method according to the invention as described in Example 1;

Fig. 2 is a plan view of the device shown in Fig. 1;

Fig. 3 illustrates in longitudinal section a device for carrying out the method according to .the invention as described in Example 1.

Fig. 4 shows the same device asseen-from above, with part of the cover removed;

Fig. 5 is an illustration of another device used in carrying out Example 3, and

Fig. 6 is yet another device to beused in Example 4.

' Example 1 Referring to Figs. 1 and 2, a container I 0 is mounted on a shaft I9 in a bearing 20.

I I. In the container, there are two rollers I2 and I3, which form a deforming device for the aluminum alloy to'be prepared for subsequent extr'action' A lump of alloy to be fed through the rollers is desigated by It, another lump emerging from the'rollers after deformation, by IT." Roller I2 is supported by a standard I4 and Roller I3 is mounted on a'shaft H in a bearing 22 of sufficient width to permit shaft 2| to move toward roller I2 under the action of a spring I8.

In operation, an alloy consisting of 34% silicon, 64% aluminum, 1.2%. iron, remainder oxide and carbides, i passed'through the rollers I2 and I3 of the above described device, roller I3 being forced by the action of spring I8 toward roller I2, thereby causing a piece of aluminum alloy I It to be deformed in passing.

The alloy is fed to the container in rough pieces of an average diameter of 30-50 mm.

The deformation is performed under liquid mercury. Preferably the mercury level is made to stand above the rollers as shown and the pieces of the aluminum alloy are fed between the rollers from underneath automatically, floating upward between the rollers owing to their buoyancy in the mercury, and thus being deformed while submerged.

While a lump of alloy of the type described, when dressed in air, is not appreciably attacked by mercury, a lump deformed by passing through rollers below mercury, when broken up, shows the metal crystals to be penetrated by mercury.

If the thus pre-treated alloy is exposed to the effect of mercury at 350 0., aluminum is immediately dissolved corresponding to the solubility at this temperature.

Example 2 a drawer- In operation an aluminum scrap alloypomprising 4% copper, 94%, aluminum, and 2% other alloy components is liquified at about 68.0? (3. 'andw introduced into vessel shaking motion.

33, which is "so arranged on the wheel 34 that it can-*perfor'nna strong" Mercury vapor is introduced iwithoutrpressu-rezzr through 3 l Under constant permitted to cool off in thehnercury vapor atmosphere 'runtil the?temp'eratureizzhas fallen below the normalfboilingspoint of mercuryw:

thus displacing the air at 32.

The aluminumsalloy hasxbyithat time'solidified to Ya granular: mass, the -indiividual: elements .of which are about the size of a pinhead. The particles are completely wettedwith mercury on their surface. Emamplerd Fig." 5 shows'thedevice-used." A closed container 40 has aninjector'li mounted in one of the sidewalls, a retort 42 is arranged in the container and has a connection 43 to pipeM'. .The retort is filled v'vith'liquiid aluminum alloy 44 "55 designates vaporized alloy, and 46 the alloy after it has deposited on the"bo'ttom"of container 40.

In operatioir ranr. aluminum .zall'oy --comprising 30 of silicon; .1 168 of*:aluminum:: and' slight amounts of other -components:Lis:introduced at the start :into '-.retort' 42. i Mercury-vapor :is' intro--:

duced under pressure. through: injection pipe 4 l i shaking, the fluid meter-is theirliquid aluminumalloy is suckeditfrom. the retort and atomized by the mercury v-apor, as shownsat 45: The dispersed alloy, 'wetted withzzmercury, is

immediately attacked .by' the latter: if 1 below, its.

boiling "point, even ats moderate:ixtemperaturesyzi and a higher'aluminum 'extractionrensues when the deposit-Mi; after cooling=off ,:iis subjectedato'i extraction.

Example 4 5 Fig.6 showsthedevice to'be't used. The device Number comprises again a closed vessel 50. Mounted in the container is a roller 5| rotatably mounted on a shaft 52. About one-third of the roller dips into the mass of boiling mercury 53. Mounted in one of thecontainer wallsis ajunneljd with a pipe--55 for admission 19f the l quidalloy. 5% designates a vent pipe, and 51 a cooler.

In carrying out the method according to this modified embodiment of the invention, a liquid alloy comprising 30%.-:of silicon, 57% of alumi num; and a remainder of iron, titanium, and so on, is caused-to-flowthrough funnel 54 and pipe Sionto; the revolving, roller 5| which dips into boiling mercury .53.; i'I'he alloy is distributed over the:rol1er. and.-enters the mercury in a thin film grating said alloysin liquid state in thepresence of fluid. mercury and under exclusiom of air, thereby causing the formation of newsurfaces in the particles obtained=by disintegration-of said alloys and enabling the mercury to perform an immediate wetting action on saidynewly-iormed surfaces.

2. In the process according-to claiml, efiectingalloy by means of a jet of gaseous mercury.

4. -Inthe process accordingto claim -1-, wherein thedisintegration-of-thealumin mealloyin liquid form- ;occurs ;in ,liquidymereury References Cited in' the' file"of this patent UNITED. STATES :1 IFENT Name Date Loevenstein; Feb. 16, 1943 Bailey-ct 8.1.; Nov. 21, 1882 Loevenstein-'-- July 4, 1950 ef ec n the disintegration byppraying-a; liqu d-aluminum Pugh June 26; 1951 

1. THE PROCSS OF DRESSING ALUMINUM ALLOYS IN PREPARATION FOR THE EXTRACTION OF THE ALUMINUM BY MEANS OF MERCURY, WHICH COMPRISES DISINTEGRATING SAID ALLOYS IN LIQUID STATE IN THE PRESENCE OF FLUID MERCURY AND UNDER EXCLUSION OF AIR, THEREBY CAUSING THE FORMATION OF NEW SURFACES IN THE PARTICLES OBTAINED BY DISINTEGRATION OF SAID ALLOYS AND ENABLING THE MERCURY TO PERFORM AN IMMEDIATE WETTING ACTION ON SAID NEWLY FORMED SURFACES. 